High moisture reading on stone tile bathroom floor

**Ken Carr** · 07-22-2009, 08:46 PM

I came across this in an inspection I did this week and am very puzzled. I was wondering if anyone has come across this situation or has any ideas.

I normally run a Tramex moisture meter around the toilet area to pick up any leaks from an ill-fitting toilet flange. On this inspection, the meter registered at the highest setting. I moved the meter around and the entire floor was high. I tested the other bathroom and got the same readings. I ran the meter on the tiled walls and the floor outside each bathroom to see if I could pick anything up. Everything there was normal.

The floor is a honed stone (no glaze/not polished). The developer's agent thought that the stone could be porous and absorbed water when the apartment was mopped a couple of hours prior to the inspection. This seemed plausible to me so I scheduled a return trip today, approx. 48-hours later to re-test. I received the same results. Furthermore, as a back-up, I brought my Protimeter today and it registered the same as the Tramex.

Has anyone come across this? Or have any ideas? I asked the developer if they had a piece of un-installed stone to test that separately as a control. But of course they didn't.

Any comments would be greatly appreciated. Thanks!

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Ron Bibler · 07-22-2009, 08:53 PM

You may have a wire mesh under the tile. this will send the meter off in the red.

Can you get under this floor? If yes check the wood under that area.

Best

Ron

Ron Bibler · 07-22-2009, 08:57 PM

If you have high moisture from the bathroom tile. what did you get in the adjacent rooms and base of the adjacent walls. if its that wet you should find some moisture to the adjacent wood floors and base of the adjacent walls.

Best

Ron

**Ken Carr** · 07-22-2009, 09:08 PM

Ron,

This is a Condo unit on the 3rd floor in NYC. As such, I cannot see the underside of the floor.
However, I did check out the ceiling in the 2nd floor unit directly under the bathrooms. Meter readings were normal. Also checked out bathrooms in 3-other units and got the same high readings.
The wood floors adjacent to the bathrooms read normal.

I thought about the wire mesh but no one can tell me how the floors were installed. Even though it is a brand new building! So who knows.

What puzzles me is that I have inspected many apartments in new construction in NYC and this is the first time I got readings like this.

Thanks for your response.

Ken

Ron Bibler · 07-22-2009, 09:13 PM

I would note your finding and require further information or more information on the floors material list.

If you have access to an Infrared Camera. that may provide you with another layer of information.

Best

Ron

Michael Garrity · 07-23-2009, 05:35 AM

If the building is new then maybe the bathrooms are just drying out?Concrete floor?Mud job under the tile?

**Raymond Wand** · 07-23-2009, 06:01 AM

Have never used a Tramex, but did you calibrate the instrument before use to ensure its accuracy?

**Ken Carr** · 07-23-2009, 06:25 PM

Originally Posted by Raymond Wand

Have never used a Tramex, but did you calibrate the instrument before use to ensure its accuracy?

I have not re-calibrated it. However, on Day 2 I used it in conjunction with a Protimeter with the same results.

**Ken Carr** · 07-23-2009, 06:27 PM

Originally Posted by Michael Garrity

If the building is new then maybe the bathrooms are just drying out?Concrete floor?Mud job under the tile?

I thought that this was maybe the case but I don't get high readings anywhere else in the unit. The construction is cement slab so I assume I would also get a high reading through the wood floors if this was the case.

Michael Garrity · 07-23-2009, 06:37 PM

radiant floor heat?water pipes?

**John Kogel** · 07-23-2009, 08:50 PM

Originally Posted by Michael Garrity

radiant floor heat?water pipes?

My guess would be that or wire mesh or a high iron or copper content in the stone? The moisture meter measures resistance, not necessarily moisture.

Moisture from leaks is almost always concentrated at the wet spot, so it's in patches, not continuous over the whole surface.

**Ken Carr** · 07-24-2009, 05:46 AM

Originally Posted by John Kogel

My guess would be that or wire mesh or a high iron or copper content in the stone? The moisture meter measures resistance, not necessarily moisture.

Moisture from leaks is almost always concentrated at the wet spot, so it's in patches, not continuous over the whole surface.

No radiant heat in the floor.
Good point about it not being continuous over the whole surface.
I don't think that there is a leak. I just want to cover myself.

**Stuart Brooks** · 07-24-2009, 07:40 AM

Originally Posted by Ken Carr

I have not re-calibrated it. However, on Day 2 I used it in conjunction with a Protimeter with the same results.

My Protimeter was giving solid RED wet signals on a painted concrete floor. Then noticed it would show max wet conditions on just about any concrete. I contacted GE and was told that not only metal but the salts in cured concrete can cause a false reading.

I wonder if a surface with covered with lead paint would also cause the meter to give false readings?

gary gramling · 09-07-2009, 01:32 PM

While there may not be a wire mesh under the floor, there are most likely steel beams acting as floor joists. The light weight concrete could still transmit the conductivity through to the stone floors, giving a false reading. I got the same type of reading with a Tramex on a slate floor in a fifth floor condo. In the rest of the condo, the wood floor could be serving as a barrier to conductivity, as long as it is dry.